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//go:build extra
// +build extra
package extra
import (
"bytes"
"errors"
"fmt"
"io"
"log/slog"
"mime/multipart"
"net/http"
"os/exec"
"strings"
"sync"
)
type WhisperServer struct {
logger *slog.Logger
ServerURL string
SampleRate int
AudioBuffer *bytes.Buffer
recording bool // protected by mu
mu sync.Mutex // protects recording & AudioBuffer
cmd *exec.Cmd // protected by cmdMu
stopCh chan struct{} // protected by cmdMu
cmdMu sync.Mutex // protects cmd and stopCh
}
func (stt *WhisperServer) StartRecording() error {
stt.mu.Lock()
defer stt.mu.Unlock()
if stt.recording {
return nil
}
// Build ffmpeg command for microphone capture
args := []string{
"-f", "alsa",
"-i", "default",
"-acodec", "pcm_s16le",
"-ar", fmt.Sprint(stt.SampleRate),
"-ac", "1",
"-f", "s16le",
"-",
}
cmd := exec.Command("ffmpeg", args...)
stdout, err := cmd.StdoutPipe()
if err != nil {
return fmt.Errorf("failed to get stdout pipe: %w", err)
}
stt.cmdMu.Lock()
stt.cmd = cmd
stt.stopCh = make(chan struct{})
stt.cmdMu.Unlock()
if err := cmd.Start(); err != nil {
return fmt.Errorf("failed to start ffmpeg: %w", err)
}
stt.recording = true
stt.AudioBuffer.Reset()
// Read PCM data in goroutine
go func() {
buf := make([]byte, 4096)
for {
select {
case <-stt.stopCh:
return
default:
n, err := stdout.Read(buf)
if n > 0 {
stt.mu.Lock()
stt.AudioBuffer.Write(buf[:n])
stt.mu.Unlock()
}
if err != nil {
if err != io.EOF {
stt.logger.Error("recording read error", "error", err)
}
return
}
}
}
}()
return nil
}
func (stt *WhisperServer) StopRecording() (string, error) {
stt.mu.Lock()
defer stt.mu.Unlock()
if !stt.recording {
return "", errors.New("not recording")
}
stt.recording = false
// Stop ffmpeg
stt.cmdMu.Lock()
if stt.cmd != nil && stt.cmd.Process != nil {
stt.cmd.Process.Kill()
stt.cmd.Wait()
}
close(stt.stopCh)
stt.cmdMu.Unlock()
// Rest of StopRecording unchanged (WAV header + HTTP upload)
// ...
stt.recording = false
// wait loop to finish?
if stt.AudioBuffer == nil {
err := errors.New("unexpected nil AudioBuffer")
stt.logger.Error(err.Error())
return "", err
}
// Create WAV header first
body := &bytes.Buffer{}
writer := multipart.NewWriter(body)
// Add audio file part
part, err := writer.CreateFormFile("file", "recording.wav")
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
// Stream directly to multipart writer: header + raw data
dataSize := stt.AudioBuffer.Len()
stt.writeWavHeader(part, dataSize)
if _, err := io.Copy(part, stt.AudioBuffer); err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
// Reset buffer for next recording
stt.AudioBuffer.Reset()
// Add response format field
err = writer.WriteField("response_format", "text")
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
if writer.Close() != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
// Send request
resp, err := http.Post(stt.ServerURL, writer.FormDataContentType(), body) //nolint:noctx
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
defer resp.Body.Close()
// Read and print response
responseTextBytes, err := io.ReadAll(resp.Body)
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
resptext := strings.TrimRight(string(responseTextBytes), "\n")
// in case there are special tokens like [_BEG_]
resptext = specialRE.ReplaceAllString(resptext, "")
return strings.TrimSpace(strings.ReplaceAll(resptext, "\n ", "\n")), nil
}
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